Vulcanizable EPDM containing rubber composition

Abstract

A rubber composition is disclosed containing an ethylene-propylene-nonconjugated diene copolymer rubber (or a blend of an ethylene-propylene-nonconjugated diene copolymer rubber and a diene rubber), a specific alkoxysilane compound, and amorphous silica powder having a specific surface area of 50 to 100 m2/g (BET adsorption). The vulcanized rubber is prepared by vulcanizing such a rubber composition. The rubber composition is excellent in dynamic characteristics and also in mechanical characteristics, dynamic fatigue resistance and thermal aging resistance. It also can provide a vulcanized rubber having the above-mentioned effects.

What is claimed:  
     
       1. A vulcanizable rubber composition, comprising: 
       (a) an ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) having a Mooney viscosity (MS 1+4 , 160° C.) of 40 to 80, wherein the diene is selected from the group consisting of 1,4-hexadiene; 1,6-octadiene; 2-methyl-1,4-hexadiene; 6-methyl-1,5-heptadiene; 7-methyl-1,6-octadiene; cyclohexadiene; dicylopentadiene; methylterahydroindene; 5-vinylnorbornene; 5-ethylidene-2-norbornene; 5-methylene-2-norbornene; 5-isopropylidene-2-norbornene; 6-chlormethyl-5-isopropenyl-2-norborene; 2,3-diisopropylidene-5-norbornene; 2-ethylidene-3-isopropylidene-5-norbornene; and 2-propenyl-2,2-norbornadiene; and a sufficient amount of a cross-linking system capable of crossing the rubber;  
       (b) at least one of the alkoxysilane compounds selected from the group consisting of bis-3-(trimethoxysilyl)propyl-tetrasulfane; bis-3-(triethoxysilyl)propyl-tetrasulfane; bis-3-(tripropoxysiliyl)propyl-tetrasulfane; and 3-Butene-triethoxysilane;  
       (c) silica and/or silicate powder having a BET specific surface area of 50 to 100 m 2 /g; and  
       (d) carbon black with a specific surface area ranging between 5 to 90m 2 /g in an amount of 0.1 to 60 parts by weight, and/or a mineral filler with a specific surface area ranging between 1 and 30m 2 /g in an amount of 0.1 to 100 parts by weight.  
     
     
       2. A vulcanizable rubber composition, comprising: 
       (a) an ethylene-propylene-nonconjugated diene copolymer rubber (EPDM);  
       (b) an alkoxysilane compounds according to formula (I); and  
       (c) silica and/or silicate powder;  
       wherein formula I is as follows:                    
       wherein 
       R is an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms;  
       R 1  is an alkyl group having 1 to 4 carbon atoms or is a phenyl group;  
       n is 0, 1 or 2;  
       R 2  is a divalent saturated straight-chained or branched hydrocarbon radical having 1 to 6 carbon atoms;  
       R 3  is an arylene group having 6 to 12 carbon atoms;  
       m is 0 or 1;  
       p is 1;  
       q is 1 or 2; and  
       B is —SCN or SH when q is 1, or B is —Sx- when q is 2, where x is an integer of from 2 to 8.